JDK 8的Maven问题：不支持的major.minor版本52.0

Question

Apologies if my question is a duplicate of any other items previously mentioned here .

I have the following configuration :

Ubuntu 14.04 64 bit JDK 1.8u45 Maven v3.3

I am trying to package my code into a deployable war.

The war gets created succesfully , but on accessing it on my browser , I am running into Unsupported major.minor version 52.0 errors.

On Googling around I saw that this is due to a mismatch in installed JDK and the maven-compiler level.

But in my case , both are the same. -> JDK 1.8 and maven-compiler version 3.3 with source and target 1.8.

What can I do to get my build to compile successfully ?

Outputs of some helpful commands :

mvn -v

root@labuser-OptiPlex-3010:/# mvn -v 
Maven home: /usr/local/apache-maven-3.3.3 
Java version: 1.8.0_45, vendor: Oracle Corporation 
Java home: /usr/local/jdk1.8.0_45/jre Default locale: en_IN, platform encoding: UTF-8 OS name: "linux", version: "3.16.0-43-generic", arch: "amd64", family: "unix" 

Answer 1

mvn -v will tell you what Java version maven is using. Run that in your console, it will probably show you that it uses the wrong Java version.

Answer 2

Since you mentioned you can successfully create the war with maven, it sounds like JDK 8 is being used as expected during the build. The problem is your server is apparently running using an older version of Java. Although you only installed JDK 8 yourself, you must have already had an older version of Java on your computer. Make sure JAVA_HOME is set to JDK 8 and that your server sees that version properly. See if you have a JRE_HOME env variable set as well, and point it to JDK 8 as well.

Answer 3

I got the solution by running :

<tomcat-root-dir> / bin > catalina.bat version.

It showed that the JDK on my machine was JDK1.7 where as the one used to compile the WAR was 1.8.

Thanks to everyone for their inputs.